1. Field of the Invention
This invention relates, to a device for eliminating a gap of the threaded rod of a plane machine, particularly to one able to stabilize the planing table of a plane machine during planing so as to carry out planing smoothly and precisely and elevate the quality of planing.
2. Description of the Prior Art
A conventional plane machine, as shown in FIG. 1, includes a bottom base 11, four threaded rods 12 and a planing table 13 combined together. The four threaded rods 12 are respectively fixed at the four corners of the bottom base 11, extending upward and screwed through the planing table 13. The planing table 13 able to be moved up and down is provided thereon with a planing knife for carrying out planing of wood materials. The planing table 13 has four threaded rod bases 131 respectively fixed at its four corners and screwed with the four threaded rods 12, enabling the planing table 13 to move up and down along the threaded rods 12.
However, as shown in FIG. 2, the threaded rod base 131 of the planing table 13 has its inner threads 1311 screwed with the outer threads 121 of the threaded rod 12; therefore backlash (a) of different sizes may form between the inner threads 1311 and the outer threads 121. Further, the planing table 13 has a certain weight so the inner threads 1311 of the threaded rod base 131 may be forced by the weight of the planing table 13 to press the upper side of the outer threads 121 of the threaded rod 12, forming a gap (a) between the inner and the outer threads 1311 and 121 above the inner threads 1311. On the other hand, when the planing machine carries out planing, the wood material being planed will produce a reverse pushing-up force to push against the planing knife and the planing table 13. As there forms the gap (a) between the inner threads 1311 of the threaded rod base 131 of the planing table 13 and the outer threads 121 of the threaded rod 12, the planing table 13 together with the threaded rod base 131 will be actuated by the reverse pushing force of the wood material to move upward for nearly the distance of the gap (a), if the reverse pushing force pushing against the planing table 13 is greater than the total weight of the planing table 13. At this time, the planing position of the planing knife 14 will become a bit higher than the original one by the distance of a gap (b), and the planing surface of the wood to be planed subsequently will become a little more bulgy than the original one, resulting in an uneven planing surface 151, as shown in FIG. 3. And such an uneven planing surface 151 will always appear especially when the planing table 13 is frequently moved up and down or has been employed for long to render the inner threads 1311 of the threaded rod base 131 and the outer threads 121 of the threaded rod 12 worn off seriously. Apparently, it is of great importance to solve the problem of the gap formed between the threads of the threaded rod base 131 and the threaded rod 12 so as to stabilize the planing table 13 in a planing process and elevate the quality of planing.